1. wk 2 fundamentals of X-Ray physics Flashcards

1
Q

___ is the smallest quantity of electromagnetic NRG

A

photon

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2
Q

___: radiation that has enough NRG to eject e- from electrically neutral atoms, leaving a charged atom

A

Ionization radiation

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3
Q

What is the difference btw x-rays and gamma rays

A

x ray- produced in the e- cloud of artifically excited atoms

gamma- produced inside the nucleus of radioactive atoms

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4
Q

how are x rays produced

A

in an e- cloud of artifically excited atoms

gamma- radioactive atoms

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5
Q

how are gamma rays produced

A

inside the nucleus of radioactive atoms

xray: artifically excited

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6
Q

(4) sources of naturally occuring enviro radiation

A

radon
cosmic rays
terrestrial radiation
deposited radionucleotides

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7
Q

**What are three sources of man-made radiation

A

medical x-rays
nuclear medicine
consumer products

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8
Q

photons travel at the speed of ___

A

light

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9
Q

(6) characteristics of a photon

A
  1. no mass
  2. travel at the speed of light ( c)
  3. have variable wavelengths/ freq
  4. NRG and freq are directly proportional
  5. electrically neutral
  6. inverse square law
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10
Q

1st rule of radiation

A

ALARA

as low as reaasonably achievable

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11
Q

what does ALARA mean

A

as low as reasonably acheivable

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12
Q

4 ways to maintain safe radiation exposure

A

filtration
collimation
protective apparel
protective barriers

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13
Q

____ are inserted into the x ray machine in order to absorb low NRG x rays (filtration)

A

metal filters

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14
Q

Low NRG x ray is ____!

A

garbage

- does not penetrate the PT

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15
Q

high NRG x rays go through the pt and produce ____

A

shadows

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16
Q

____: method of restricting the x ray beam to the part of the body of interest

A

collimation

- also increases the image quality

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17
Q

_____ are used by pt and techs to reduce unwanted exposer

A

lead-lined shields/ aprons

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18
Q

____ are xray videos

A

fluoroscopy

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19
Q

Units: (R)

A

roentgen
- unit of radiation exposure

  • most x ray images are in (mR) 1mR= 0.001R
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20
Q

Units: (rad)

A

radiation absorbed dose

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21
Q

units: (rem)

A

equivalent dose

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22
Q

Units: (LET)

A

linear energy transfer

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23
Q

___: unit of radiation exposure. measures the ability ot ionize air

A

roentgen ( R)

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24
Q

SI units of ( R)

A
air kerma (Gya)
1R= 0.01 Gya
0.00001= 10^-5Gya
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25
Q

Air kerma is the SI unit for ___

A

Roentgen ( R)

1R= 0.01Gya

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26
Q

___: is a measurement of the amt of radiation deposited into a mass (soft tis)

A

Adsorbed Dose (rad)

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27
Q

SI unit of absorbed dose (rad)

A

gray

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28
Q

Unit: (Gyt)

A

gray

- SI units of absorbed dose (rad)

29
Q

1rad = ____ Gyt

A

1 rad = 0.01 Gyt

1 gyt= 100rad

30
Q

___: amt of radiation received by a person

A

dose equivalent (rem)

31
Q

Unit: rem

A

dose equivalent

32
Q

SI unit of rem

A

seivert (SV)

33
Q

1 rem= _____ SV

A

0.01SV

34
Q

what medical procedure gives off the most dose of x ray to a pt

A

Body CT

- 100s of x rays taken at one time

35
Q

What medical procedure gives off the least x ray to a pt

A

dental

- one tooth at a time

36
Q

which gives off x rays: CT or MRI

A

CT

- MRI is magnets

37
Q

_____: unit of quantity of radioactive material (not radiation emitted by the material)

A

Curie (Ci)

nothing to do with x rays

38
Q

Unit: Ci

A

Curie

nothing to do with x rays

39
Q

SI unit of Curie (Ci)

A

becquerel (Bq)

40
Q

Unit: Bq

A

becquerel

41
Q

a curie is a measure of ___

A

radioactivity

42
Q

_____: a measure of the rate at which NRG is transferred from ionizing radiation to soft tiss

A

linear energy trasnfer (LET)

43
Q

Unit: LET

A

linear energy trasnfer

44
Q

the unit of LET is ___

A

keV/um

- kiloelectron volt of NRG/ micrometer of soft tiss

45
Q

the LET of diagnotic x rays is around _____ for regular x rays

A

3kEV/um

46
Q

ionizating radiation to produce a bio effect ____ as the LET of radiation increases

A

increase

47
Q

Unit: RBE

A

relative biological effectiveness

48
Q

_____: a relative quantification of the ability of radiation to produce biologic DAMAGE

A

relative biologic effectiveness (RBE)

49
Q

RBE= _________/ _______

A

Dose of standard radiation necessary/ dose of tested radiation necessry

50
Q

the RBE of diagnostic x rays is ___

A

1

51
Q

radiations with ____ LET than diagnostic x rays have an RBE less than 1

A

lower LET

  • less intense x ray
52
Q

Radiations with ___ LET have a higher RBE

A

higher

- more intense x ray

53
Q

x ray travel in a straight line in a ____ beam

A

divergent beam

54
Q

a character of x ray is to produce ___ radiation

A

scatter

55
Q

____ is an entity that varies in space and time

A

wave

56
Q

(3) defining characteristics of a wave

A
  1. wavelength
  2. freq
  3. velocity
57
Q

____: distance over which the waves shape repeats

A

wavelength

measured in meters or cm

58
Q

____: number of waves per unit of time

A

frequency (Hz)

59
Q

___= wavelength x freq

A

velocity (m/s)

60
Q

all x rays travel at a ___ speed

A

constant

61
Q

the shorter the wave the higher the ___

A

frequency

62
Q

the shorter the ___ the higher the freq

A

wave

63
Q

**the wavelength and freq are ____ proportional

A

inversely

64
Q

visible light photons tend to act more like ___

A

waves

  • x ray photons act like particles
65
Q

x ray photons tend to act more like ___

A

particles

  • light photons act like waves
66
Q

intensity of x rays is inversely proportional to the ____

A

squarre of the distance traveled

67
Q

as the distance from radiation _____ the intensity of the beam ____

A

increase/ decrease

decrease/ increase

68
Q

Inverse square law:

A

the intensity of x rays is inversely proprotional to the square of the distance traved